Printing ink



Patented Feb. 9, 1937 UNITED STATES PATENT OFFICE No Drawing.Application May 20, 1935, Serial No. 22,437

10 Claims.

copending application Serial No. 711,229, Patent Among the objects ofthis invention are those of producing an ink which has an excellentprintability, which is quick drying, which will not skin or dry in thefountain, and which, upon operating the press after the press has beenleft standing, will plasticize or make printable the ink which has driedon the plate and rollers.

It is also an object of this invention to produce an ink in which thecoloring matter may be either or both pigments and dyes.

In printing upon paper or other types of printable surfaces, such as forexample, paper which may be used for wrapping bread, it is desirable tocombine into a continuous operation the printing upon the paper web andthe winding of the same into a roll. In so doing it is desirable thatthe ink should be dry before the web is wound into a roll otherwise theink on the printed surface will ofiset on to the unprinted surface whichcontacts with the same. To expedite the printing and rolling operationthe printed web is usually subjected to heat of a degree higher thanroom temperature. The temperature necessary to completely evaporate theliquid and solvents in the ink will be governed to a great extent by thespeed of the press and the fact that it is not desirable to subject thepaper to heat of such a high temperature that the moisture in the paperis evaporated or driven oil. The evaporation of the moisture in thepaper causes the same to become brittle and impairs the utility of theIt is an object of this invention to produce an ink that is quick dryingand which, after being applied to the printable surface, will not causesticking of one printed sheet or layer to another.

This invention also contemplates an ink that will not smear during theslipping incident to the early stages of winding or rolling the printedweb.

Another important feature of this ink is that upon being applied to theprintable surface it leaves no residual odor; This permits the printedfinished work to be used immediately without airing and rewinding whichis the common practice with inks that dry by oxidation.

The improvements in the ink which comprises this invention over thatdescribed and claimed in my copending application reside in thefollowing factors: (1) The drying temperature range has been appreciablylowered thus permitting higher printing press speeds. (2) Theintroduction of higher viscosity cellulose esters. (3) The introductionof dyes as well as pigments and the combination of pigments and dyes forcoloring matter. (4) The inclusion of the esters and ethers of ethyleneand diethylene glycol as solvents and diluents. (5) The inclusion ofelecresin esters and alkyd resins as vehicles and lubricants.

The temperature range for drying this ink may vary from 150 F. at verylow press speeds where the printed web travels in the neighborhood ofabout to feet per minute and the ink has approximately about 11 or 12seconds to dry, to a point where the paper scorches which will probablybe around 325 F. The most eflicient drying temperature range for thepresent ink appears to be from 220 to 260 F. when the press speeds rangefrom a low speed of 250 feet per minute upwards to a relatively highspeed of 500 feet per minute. Satisfactory printing operations have beenperformed with this ink where the drying temperature ranged from F.upwards to the scorching point of the paper and the press speed rangedfrom '75 to 500 feet per minute.

The rate at which the ink will dry depends upon several variable factorssuch as temperature, the speed at which the printed web travels, thetime period of contact with the heating roll, the thickness of the paperwhere the heat is applied by means of a roll to the underside of theprinted paper or web, and the method or apparatus used for heating theprinted ink. This ink dried very eificiently when applied to a sulphidepaper web approximately .004 of an inch thick where the printed web washeated by being passed over a heating roll at 240 F. so that theunderside or non-printed side of the paper contacted with the heatingroll for a period of two and one-half to three seconds.

As a binder a cellulose ester is used. This cellulose ester may benitrocellulose or cellulose acetate or a combination of both. Theviscosity of the nitrocellulose or the cellulose ester may range fromonefourth second to forty seconds. The proportion of nitrocellulose orcellulose acetate binder, figured on a dry basis by weight, should notbe less than 3% nor more than 18% of the total. Excellent inks areproduced with nitrocellulose as a binder where the nitrocellulosecontent ranges from 6% to 12%. However, as above stated, this range maybe from 3% to 18%.

The alkyd resins may be used alone or may be hydrocarbons and fatty acidesters.

modifledwith fatty acids or resin acids such as gum resin and ester gum.

As a vehicle and lubricant for the pigment carnauba wax may be used asspecified in my Patent 2,002,537. However, the use of resins ispreferred. Two types of resins may be used, namely: (1) oleo resinesters which includes esterified dammar, elemi, balsams, and colophony,and (2) alkyd resins which are glycerol phthalates. The preferable resincontent ranges from 12% to 25% of the total by weight of the finishedink, but satisfactory ink can be manufactured with a resin contentranging from 1% to 50%.

As a solvent and diluent glycol derivatives are used. These glycolderivatives are esters or ethers of either ethylene glycol or diethyleneglycol. Preferably these glycol derivatives are used alone as solventsand diluents. However, these glycol derivatives may be used incombination with one or more of the benzene hydrocarbons such asbenzene, toluene, xylene, or even higher fractions. These glycolderivatives may also be used in combination with some fatty acid esterssuch as the acetates of methyl, ethyl, propyl, butyl, or amyl alcohols.The glycol derivatives may also be used in combination with the benzeneHowever, preferably the glycol derivatives are used alone.

Among the glycol derivatives which may be used are the following:

Ethylene glycol (Cellosolve) mono-ethyl ether E t h yl e n e g 1 yo 0](Butyl cellosolve) mono-butyl ether E t h y l e n e g l y c 01(Cellosolve acetate) mono ethyl e t her acetate Diethylene glycol mono-methyl ether acetate Diethylene glycol mono methyl ether Diethyleneglycol mono ethyl e t h e r acetate Diethylene glycol mono-ethyl etherDiethylene glycol mono-butyl ether The concentration of these solventsand diluents can range from 40% to of the total by weight. The exactconcentration of the solvent and diluent will, of course, vary withinthis range depending upon the kind of ink desired.

As a coloring matter pigments, dyes, and the combination of pigments anddyes are used. Among the dyes that can be used in any dye which can bedissolved in the above-mentioned solvents such as methyl violet,malachite green, Victoria blue, methylene blue, rhodamine. A dyeconcentration as high as 15% by weight of the finished ink may be used.However, a dye concentration not greater than 10% by weight of thefinished ink is preferable in vmany cases. When the coloring matterconsists of a pigment, the pigment figured on a dry basis may range from5% to 65% by weight of the ink. When a filler is used in addition to thecoloring pigment, then the total of the filler and the pigment shouldbe'held within this range.

These various ingredients may be mixed in any of the well-known ways,such as in a paddle agitator or in a rolling mill. In some cases where(Methyl carbitol acetate) (Methyl carbitol) (Carbitol acetate)(Carbitol) (Butyl carbitol) the coloring matter consists of a dye and nocoloring pigment or filler is used, the ink may be satisfactorily mixedin a paddle agitator and the passing of the mix through a grinding millis unnecessary.

Carnauba wax may be used in place of the resins. In such case theabove-mentioned glycol derivatives may be used as solvents and diluentsor, if desired, ethylene glycol may be used as a solvent.

I claim:

1. A printing ink consisting of coloring matter, 3% to 18 by weight of acellulose ester ranging in viscosity from one-fourth second to fortyseconds, 1% to 50% of an oleo resin ester, and 40% to 90% of a glycolderivative from the class consisting of the esters and ethers ofethylene glycol and diethylene glycol.

2. A printing ink consisting of coloring matter, 3% to 18% by weight ofa cellulose ester ranging in viscosity from one-fourth second to fortyseconds, 1% to 50% of an alkyd resin, and 40% to 90% of a glycolderivative from the class consisting of the esters and ethers ofethylene glycol and diethylene glycol.

3. A printing ink consisting of coloring matter, 3% to 18% by weight ofa cellulose ester ranging in viscosity from one-fourth second to fortyseconds, 12% to 25% of an oleo resin ester from the group consisting ofesterified dammar, elemi, balsams, or colophony, and 40% to 90% of aglycol derivative from the class consisting of the esters and ethers ofethylene glycol and diethylene glycol.

4. A printing ink consisting of a spirit or oil soluble dye, soluble ina glycol derivative, from the group consisting of methyl violet,malachite green, Victoria blue, methylene blue, and rhodamine, 3% to 18%by weight of a cellulose ester ranging in viscosity from one-fourthsecond to forty seconds, 1% to 50% of a resin, and 40% to 90% of aglycol derivative from the class consisting of the esters and ethers ofethylene glycol and diethylene glycol.

5. A printing ink consisting by weight of coloring matter from 5% to 65%of dry pigment, 3% to 18% cellulose ester ranging in viscosity fromone-fourth second to forty seconds, 1% to 50% resin from the groupconsisting of oleo resin esters and alkyd resins, and 40% to 90% of aglycol derivative from the class consisting of the esters and ethers ofethylene glycol and diethylene glycol.

6. A printing ink consisting by weight of coloring matter of not morethan 15% dye soluble in a glycol derivative, 3% to 18% cellulose esterranging in viscosity from one-fourth second to forty seconds, 1% to 50%resin from the group consisting of oleo resin esters and alkyd resins,and 40% to 90% of a glycol derivative from the class consisting of theesters and ethers of ethylene glycol and diethylene glycol.

7. A printing ink which is quick drying at a temperature range from F.to 325 F., consisting of coloring matter, 3% to 18% by weight of acellulose ester of the group consisting of nitrocellulose and celluloseacetate ranging in viscosity from one-fourth second to forty seconds, 1%to 50% of a resin from the group consisting of oleo resin esters andalkyd resins, and 40% to 90% of a glycol derivative from the groupconsisting of the esters and ethers of ethylene glycol and diethyleneglycol.

8. A printing ink which is quick drying at a temperature range from 150F. to 325 F., c

sisting of coloring matter, a. cellulose ester of the group consistingof nitrocellulose and cellulose acetate ranging in viscosity fromone-fourth second to. forty seconds and comprising from 3% to 18% byweight of the finished ink, a resin from the group consisting of oleoresin esters and alkyd resins comprising by weight from 1% to 50% of thefinished ink, and a glycol derivative from the group consisting of theesters and ethers of ethylene glycol and diethylene glycol comprisingfrom to 90% of the finished ink.

9. A printing ink which is quick drying at a temperature range from 150F. to 325 F., consisting of coloring matter, a. cellulose ester of thegroup consisting of nitrocellulose and cellulose acetate ranging inviscosity from one-fourth second to forty seconds and comprising from 6%to 12% by weight of the finished ink, a resin from the group consistingof oleo resin esters and alkyd resins comprising by weight from 12% tocosity from one-fourth second to forty seconds and comprising'trom 3% to18% by weight of the finished ink, a resin from the group consisting ofoleo resin esters and alkyd resins comprising by weight from 1% to ofthe finished ink,

and a glycol derivative from the group consisting of the esters andethers of ethylene glycol and diethylene glycol comprising from 40% toof the finished ink.

EUGENE J. KELLY. Q0

